Floor surfacing machine



Aug. 29, 1939; G. DE SIPIRT 2,171,060

FLOOR SURFACING MACHINE F'iled Feb. 18, 1939 2 Sheets-Sheet l Aug. 29,1939. G, 5 sPlRT 2,171,060

I FLOOR SURFACING MACHINE Filed Feb. 18, 1939 2 Sheets-Sheet 2 Giles D01+ lm v Patented Aug. 29, 1939 UNITED STATES PATENT OFIE FLOORSURFAGING MAGHINE Giles De Spirt, Toronto, Ontario, Canada ApplicationFebruary 18, 1939, Serial No. 257,067

4 Claims. 01. 51-177) The invention has for its primary object theproduction of a more efficient and serviceable Y grinding and polishingmachine particularly adapted for terrazzo floors and the like, althoughit is not intended that its use shall be restricted to such work as theinvention might be otherwise utilized.

A further object of the invention is to provide a machine of this classin'which a grinding and polishing head comprises a shoe revoluble aboutan axis and having several stones radially disposed and each mounted togyrate about the orbit of the shoes as it turns. This is accomplished bya planetary gearing adapted to drive a complement of holding devices inwhich the stones are lodged.

The distinctive feature of gyrating the stones in the orbit of the shoeis that it increases the efficiency of the grinding andpolishing actionand performs the surfacing operation in less time.

A still further object of the'invention. is to furnish the grinding andpolishing head with a compensating mount having a rock or tilt enablingthe stones to bear uniformly on a floor irrespective of any incidentalunevenness that may exist in its surface. This compensating mount isalso advantageous in a machine of the present type in which a pair ofcoacting heads are employed since the stones are caused to adjustthemselves to the floor surface.

Having described the major objects of the invention, subsidiary objectsand advantages will be evident from the ensuing description.

Referring to the accompanying drawings, Figure 1 is a side elevation ofthe machine embodying the invention.

Figure 2 is a front elevation showing the splash cover in section.

Figure 3 is a horizontal section taken on line 3-3 of Figure 2 depictingthe left shoe with its cover removed to illustrate the planetarygearing.

Figure 4is a vertical section of one of the heads taken on line 44 ofFigure 5.

Figure 5 is a fragmentary plan viewed on line 5-5 of Figure 4 omittingthe driving shaft.

Figure 6 is a detail showing the main gear of the planetary set heldagainst rotation by flexiblering or disc members.

Figure '7 is a plan of the underside of one of the holding devices withstones set therein.

Like numerals of reference denote similar parts in each figure of thedrawings.

The conventional machine to which the invention relates comprises ahorizontal frame 8 having the head structure, generally indicated by thenumeral 9, at the front and a castor It] at the rear with a handle 5 lupwardly directed from the vicinity thereof for enabling an attendant tomanipulate the machine over a floor surface I2.

Power is furnished by an electric motor I3 mounted upon the frame 3 andsupplied with an encased chain drive it for operating gearing within thecasing i5 whereby the vertical shaft l6 of each of the twin heads isdriven at suitable speed. The shafts it are journalled in spacedhousings ll projecting downwardly from the casing I5 and rigid with thesame. Said shafts it operate in opposite directions but revolve at thesame speed. The lower ends of the housings l? are flanged and. securedto a common plate it horizontally disposed and carrying the splash cover20. Since the above construction is conventional it need not bedescribed in greater detail.

The improved mechanism will now be recounted, which concerns the headsas already mentioned, there being two of these, each driven by a shaftI6. The heads are of identical construction, hence a description of onewill suffice for the other.

The fixed plate It and. the shaft I6 constitute part of the head, theshaft It being a driving member and projecting well below the plate toafford a drive connection with a shoe 2!. The shoe 2| is a horizontalgear casing of substan tially triangular shape in plan and composed ofseparable top and bottom parts secured by fastening elements as at 22,the top part forming a cover for the bottom part. Centrally disposed inthe shoe is a stub shaft 23 secured as at 24 in a boss 25 and projectingupwardly to meet the shaft IS with which it is aligned. Shaft 23 iskeyed as at 20 so as to turn as a unit with the shoe 2|.

The meeting ends of shafts I6 and 23 are interlocked such as to providea driving connection and at the same time-enable theshoe 21 to have aslight rock or tilt. This is shown as effected by a tongue and grooveconnection 21', the tongue being rounded at its terminus and the groovebeing likewise shaped. The coupling of the shafts could of course beachieved by other known expedients in the art that provide a flexibleconnection.

The gearing within the shoe is comprised of a stationary main gear 28 inmesh with three planetary gears 29 located. equidistantly therearoundand rigidly united with shafts 30 of holding devices 3! that carry thegrinding and polishing stones 32. The shaft 3|] of each planetary gearis vertically journalled in the shoe 2| preferably by means ofantifriction bearings such as to take care of upward thrust due topressure of the stones upon the floor surface.

The main gear 28 has a bore in a hub 33, and the shafts l6 and 23 fit inthis bore, the shaft l6 having sufficient clearance to enable the shoeto rock as aforesaid. The shoe 2| is entirely journalled on the maingear 28 and to this end has a boss 34 encompassing the hub 33 and inaddition to which is furnished with an anti-friction bearing to takeupward thrust-see Figure 4.

The main gear is secured to a sub-plate 35 spaced below the plate l9 andconnected. by fastening elements to the hub 33. The sub-plate 35 ispreferably circular in extent and is supported by a plurality of arms 36depending from: the plate I9 and having inturned ends forming shouldersthat are engaged with the bottom face of the sub-plate 35. A series ofhelical compression springs 31 are interposed between the plate l3 andsub-plate 35 and circularly spaced about the shaft I6. The springs 31,of which there are 1 preferably six in number, function to retain thesub-plate 35 normally in seated position upon the shoulders of the arms36. This construction enables the shoe 2| to tilt or rock about thedriving axis so that the stones 32 of the holding devices 3| may bearevenly upon the floor surface.

Discs or rings of rubber or similar flexible material, as indicated at38, are disposed between the plate l9 and the sub-plate 35 to embracethe springs 37 which are inserted in openings. The discs or rings 38 areperipherally secured to said plates 9 and 35 by means of fasteningdevices 39 of which there are six in number equally spaced in circulararrangement. The fastening devices 39 alternately secure the discs orrings to the plate l9 and to the sub-plate 35, and thus provide aflexible connection that holds the main gear 28 against rotation and atthe same time permits the shoe 2| to rock or tilt about the verticaldriving axis. This consruction also has the advantage of cushioning thedrive so as to reduce shock and jar and to produce a smooth operatingunit.

It will be evident from the preceding descrip-' tion that operation ofthe shaft I6 of the head bodily rotates the shoe 2| and since the maingear 28 is stationary, the planetary gears 29 are revolved about theirseveral axes at comparatively high speed. Accordingly the holdingdevices 3| are rotated for causing circular motion of the stones 32thereof in the orbit of rotation of the shoe 2|. In this manner thegrinding and polishing action is promoted and expedited. As shown inFigure '7, the stones 32 are lodged in angular slots in the holdingdevices 3| and retained by wedges, there being several stones to eachholder. As the shoe 2| revolves, the spring of the compensating mountfunctions to enable the holding devices to bear uniformly upon thesurface being processed and accommodate incidental unevenness of suchsurface.

It will be understood that as there are two heads to the machine bothare similar in operation, although one rotates in opposite direction tothe other, the heads being disposed in juxtaposition and arranged tooverlap in their sweep as will be evident from an inspection of Figure3.

What I claim is:

1. In a machine of the class described, a head comprising a fixedsupport, a. driving shaft extending therefrom, a shoe extendingtransversely of the shaft, means extending radially of the shaft andproviding a concentric journal for the shoe, retaining devices seatingsaid means, springs urging said means against said retaining devices inan outward direction to counteract thrust on the shoe, and meansproviding a flexible connec- 7 tion between the driving shaft and theshoe.

2. In a machine of the class described, a head comprising a fixedsupport, a driving shaft extending therefrom, a shoe disposedtransversely of the shaft, a plate spaced from said fixed support, meansrotatably suspending the shoe from the plate coaxially with said shaft,means sustaining the plate from said fixed support, springs applyingpressure upon the shoe to counteract thrust thereon, and means providinga flexible connection between the driving shaft and the shoe.

3. In a machine of the class described, a head comprising a fixedsupport, a vertical driving shaft journalled in the support andprojecting therebelo-w, a horizontal shoe, an element carrying the shoefor rotation concentrically with the driving shaft and including a platespaced below the fixed support, said plate encircling the driving shaft,a retaining mechanism depending from the fixed support and sustainingthe plate in a manner to enable it to tilt, springs distributed aroundthe plate to exert downward pressure thereon, and means providing apower transmitting connection between the driving shaft and the shoe,said means, being constructed to permit the shoe to tilt with the plateaforesaid.

4. In a machine of'the class described, a head comprising a frameincluding a horizontal plate, a vertical shaft journalled in the frameand projecting below the horizontal plate, means for driving the shaft,a horizontal shoe, a main gear therein upon which the shoe isjournallecl, said gear having a bore receiving the vertical shaft, astub shaft secured to the shoe and projecting upwardly from the bottomthereof within said bore to meet the said vertical shaft, meansinterlocking the meeting ends of the shafts and permitting a universalmovement of the stub shaft, planetary gears journalled in the shoe andmeshed with the main gear, holding devices rotated by the planetarygears, stones therein, a disc or ring secured to the main gear at thetop of the shoe and encircling said vertical shaft, arms depending fromthe aforesaid horizontal plate and having parts supporting the disc orring, compression springs interposed between the horizontal plate anddisc. or ring to maintain the shoe in a yieldable manner whereby it mayrecede under pressure, a pliant ring encircling the vertical shaft andhaving said springs lodged in apertures therein, and fastening devicesalternately securing the pliant ring to the horizontal plate and to thedisc or ring.

GILES DE SPIRT.

